Does anyone have a parts manual for the 15B's or 175B's? I need the part number or specs for the large O ring (like 20 or 21 inches) that goes between the torque converter housing halves. Have my engine ready to go back in with the exception of this O ring...it is a little stretched and I have spent WAY too much on this rebuild to even chance it. My serial Number is L175BP 15129
Sorry, don't have the "B" parts manual, but the part # for the "C" is 321 988 R1 . May be the same for both machines? Anyway, hope this helps you in some way.
Measure the diameter of the oring groove then the thickness of the old oring
As a follow up, the 175C O''ring #321 988 R1 measures ID 19.725" X OD 20.145" x .210" Dia.